Pulsating incinerator hearth

ABSTRACT

A pulsating hearth for an incinerator wherein the hearth is suspended on a fixed frame for movement in a limited short arc to urge random size particles burning in a pile on the hearth in a predetermined path intermittently across the surface of the heart. Movement is imparted to the hearth in periodic pulses preferably by inflating sets of air bags mounted on the frame, which stroke the hearth to move it a short distance from an initial position and jar it against the frame, thus impelling the burning particles a short distance by inertia and concurrently stoking the burning pile upon each stroke, and then returning the hearth to its initial position. The hearth may also have a plurality of nozzles connected to a source of air for delivering gently flowing air to the burning pile on the hearth.

This application is a continuation-in-part of co-pending applicationSer. No. 248,054, filed Mar. 27, 1981, now U.S. Pat. No. 4,438,705 foran Incinerator with Two Reburn Stages and, Optionally, Heat Recovery.

BACKGROUND OF THE INVENTION

This invention relates to a pulsating hearth for an incinerator, and ismore particularly directed to such a hearth which is capable ofconcurrent intermittent moving and stoking of a pile of random sizeparticles burning on the hearth.

Incineration may provide acceptable means for disposing of waste, forheat processing of various materials, and for recovery of heat fromburning refuse; however, the process of incineration has had imposedupon its use severe and substantial limitation. Some incineratorsrequire removal of materials not fully combustible in prior art systemsor burnable only with undesireable side effects or hazards; thus asorting step is necessary for use of such processes and equipment. Otherincinerators need shredded material for burning and that prerequisitealso requires extra processing and equipment. Most prior artincinerators are incapable of meeting environmental standards, andrequire one or more of a wide range of auxiliary equipment, such asafterburners, scrubbers, precipitators and the like to make themfunction.

Even with suitable pre-incineration processes and equipment andauxiliary environmental protection devices, full combustion of randomrefuse material is seldom achieved, because adequate oxygenation of theburning particles is required, although the burning cannot be so rapidas to make the fire too hot or permit excessive gasification oratomization of the burning particles or the products of combustion.Optimum non-polluting combustion requires close control of the time,turbulence and temperature of the burning process. The problem isfurther magnified when the refuse contains plastics, wet refuse andliquids and when unburned particles are permitted to escape from themain burning chamber.

Preferably, the main burning chamber of an incinerator has a hearthfloor. However, such a hearth has some inherent problems requiringsolution for effective and efficient combustion of random refuse. Therefuse on the hearth must receive an even distribution of oxygen for thematerial to burn. Air must be mixed with the burning material anddispersed. Air alone, particularly with high velocities, will entrainand lift burning particles before they are fully consumed. Theuncontrolled rapid burning of the pile may also increase velocities.Such high velocities and the accompanying incomplete burning results inslagging and tends to clog up the incinerator floor, as well as topermit incompletely burned particulate and products of combustion toexit the main burning chamber of the incinerator before they areadequately consumed.

Some incinerators have been constructed using a starved air principle intheir main burning chamber, but in these devices the lack of oxygen doesnot permit the burning hydrocarbons to convert to water and carbondioxide, thus, carbon monoxide is frequently formed, representing ahazard to operating personnel and restricting use of such devices tovery well ventilated areas.

Additionally, it is often desired to control the rate and extent of theburn in the main combustion chamber, without either the risk ofpollution or the loss of desired selected unburned or ash products. Forexample, in some incinerator processes it is desired to burn perhaps 75%of each particle, but no more, and return the mostly burned particlesbefore it is entirely reduced to ash. In other processes, it is desiredto burn off readily combustible coatings and retain substrata unburnedand not damaged by heat. In these situations it is particularly usefulto control both the rate of burning and the time that the particle to beburned is subject to the heat of combustion.

SUMMARY OF THE INVENTION

By employing a pulsating hearth embodying the present invention,adequate oxygenation of the burning pile is achieved without increasingvelocities in the main burning chamber of an incinerator. Also the rateand extent of burning my be controlled.

These benefits are achieved by use of a hearth which permits the burningparticles to be moved intermittently in a shuffling fashion through theincineration area of the main burning chamber at a controlled rate. Suchmovement is provided by suspending the hearth from a fixed frame, whereit may move in a limited short arc upon receiving traumatic strokes frommechanical impetus, such as a plurality of rapidly inflating air bagswhich impell the hearth against the frame and then return the hearth toits initial stroking position. This movement, much like impelling snowfrom a snow shovel, causes the hearth to move but a short distance,slightly lifting and reshuffling the pile of burning particles andovercoming inertia to move the particles a short distance across thehearth. The action causes the burning pile to open crevices foradmitting oxygen, thus providing complete combustion. The rate of flowand burning can be controlled by the amount of air admitted to theburning pile and the frequency and strength of the stroke, and by thecushioning of the impact when the hearth strikes the frame.

The amount and velocity of air supplied to the burning pile iscontrolled by the size of the nozzles admitting air to the pile, and bythe sizing and speed of blowers and their modulation and control in theair delivering system. The frequency of the stroke may be controlled bya timer opening and closing an air line for inflating the air bags. Thestrength of the stroke may be varied by the quantity and pressure of theair delivered to the air bags. The cushioning of the impact may becontrolled by use of mechanically flexible structure, such as rubberbumpers, and by controlling sets of air bags receiving the impact of themovement of the hearth.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a pulsating hearth for anincinerator of the character described.

Another object is to provide an incinerator hearth suspended from afixed frame for movement in a short arc between an initial point and apoint of impact.

Another object is to provide means for stroking a movable hearth uponwhich a pile of particles is burning to impell the particles a shortdistance by inertia and concurrently stoking the burning pile upon eachstroke.

Another object is to provide sets of inflatable air bags mounted on afixed frame for intermittent impact with a movable incinerator hearth.

Another object is to provide a plurality of nozzles in a movableincinerator hearth which are in fluid communication with a source of airfor delivering gently flowing air to a pile of particles burning on thehearth.

Another object is to provide cushioning structure for receiving theimpact of a pulsating incinerator hearth.

Another object is to provide suspension structure for carrying apulsating hearth of an incinerator without substantially inhibiting itsmovement by friction.

Another object is to provide shelf and barrier members on a pulsatinghearth to inhibit escape of burning particles traveling thereover.

Another object is to provide means for controlling the frequency andstrength of the stroke of movements in a pulsating hearth.

Another object is to provide a gang of two or more hearths for anincinerator, one of which is constructed to move a pile of burningparticles from its surface to the surface of the adjacent hearth.

Another object is to provide step and tapered wall structure in apulsating hearth for an incinerator arranged to locate the position of apile of burning particles situated on the hearth.

Another object is to provide a plenum structure for delivery of air to apulsating hearth which serves as a rigid structural frame for thehearth.

Another object is to provide seals for a pulsating hearth which arecapable of retaining the hearth structure sealed during its movement.

Another object is to provide alignment structure for the hearth and itssuspension frame which retains the elements in position for impact andreturn for intermittent strokes during movement.

Another object is to provide a compressed air delivery and controlsystem for moving a pulsating hearth upon actuation of sets of air bagsconnected in the system.

Another object is to provide a method for controlling the rate andextent of burning of particles moved across the surface of a pulsatingincinerator hearth.

Another object is to provide a pulsating hearth for pollution free fullburning of mixed waste of random size particles in an incineratorcapable of automatic control and efficient burning as well as recoveryof heat generated by combustion.

These and other objects and advantages of the invention will become moreapparent as this description proceeds, taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of an incinerator system embodying thepulsating hearth which is the subject of the present invention.

FIG. 2 is a perspective view of a pulsatable hearth embodying thepresent invention.

FIG. 3 is a cross-sectional view of the hearth shown in FIG. 2, alongline 3--3 thereof, and, additionally showing the suspension frame andsealing structure.

FIG. 3a is a sectional view showing the sealing structure for retainingthe hearth closed within the suspension frame.

FIG. 4 is a vertical sectional view of part of the hearth and framestructure, including the means for delivering impact to the pulsatinghearth.

FIG. 5 is a top plan view of the structure shown in FIG. 4.

FIG. 6 is a detail sectional view of the toggle structure for suspendingthe hearth from its suspension frame.

FIG. 7 is an elevational view of the structure shown in FIG. 6.

FIG. 8 is a perspective view of part of a pulsating hearth, showing analternative modified structure for use when two or more hearths areganged for delivery of burning particles one hearth to the other.

FIG. 9 is a schematic representation of the desired impact and movementof the pulsations for the subject hearth over time and withacceleration.

FIG. 10 is a schematic representation of the compressed air delivery andcontrol system for pulsating the hearth.

FIG. 11 is a detail top plan view of a corner of the hearth andsuspension frame, showing an alternative modified impact cushioningstructure.

FIG. 12 is a detail section view of an alternative modified suspensionstructure for carrying the hearth on its suspension frame.

FIG. 13 is an elevational view of the structure shown in FIG. 6.

DESCRIPTION OF A PREFERRED EMBODIMENT

As shown in FIG. 1, an incinerator system, having a main combustionchamber 10, into which refuse or other materials to be burned arecharged, through an entry door 11, by means of a loading device 12,includes one or more hearths 13, upon which the refuse is to be burned.Products of combustion released by burning in the main combustionchamber 10 may be reburned in one or more afterburners 14, and, with orwithout further processing in a scrubber or other auxiliary equipment,exhausted to atmosphere through a stack 15. Ash created from burning inthe main chamber 10 may be conveyed to an ash pit 16, where the ash maybe removed by a collector system 17.

In the present invention, particularly with reference to the structureshown in FIGS. 2-7 and 9-10, the main combustion chamber 10 has a hearth13 which is capable of moving the burning material thereacross until itis ready for disposal. This moving hearth has a fixed frame 19 suspendedfrom which are toggle members 20 carrying a movable superstructure 21.The superstructure 21 has a floor 22, side plates 23, large tubularchannels 24, each defining a first set of air plenums 25, angularchannels 26, which carry step plates 27, upon which a layer of firebricks 28 are mounted, and small tubular channels 29, each defining asecond set of air plenums 30, which are secured, as by welding, to thetop wall of each of the large tubular channels 24. The central floorarea 31 and end wall 32, which is preferably tapered, together with theside wall edges 33, of the hearth, are preferably covered withrefractory material. For burning of some materials, it is possible tofabricate the entire hearth superstructure 21 from steel or similarmaterial, which preferably may be water cooled.

Passages 30a are preferably formed in the neutral area along the insidewalls of the large tubular channels 24 to permit calculation of airwithin the space defined by the floor 22, side plates 23, tubularchannels 24 and 29 and step plates 27. Air may be admitted to theinterior of the hearth 13 through air holes 24a formed in the exteriorwalls of the large tubular channels 24, and those air holes 24a may bein fluid communication with ducts (not shown) connected to air blowersfor delivery of air to the interior of the hearth 13.

Depending upon the length and number of hearths 13 used, the hearths maybe pitches or tilted in the direction of ash pit 16 to encourage gravityflow of materials burning on the hearth and to provide a longer strokeof the hearth pulsations, in a manner to be described. For example, in athree hearth system, the first hearth (closest to the entry door 11, maybe pitched about 1 inch per foot of hearth length, the second hearth maybe pitched about 1/4 inch per foot of length, and the third hearth maybe only slightly tilted. The degree of tilt is one means for controllingthe rate of flow across the burning area 31 of the hearth, and othermeans will be described hereafter.

Extending through the large and small channels 24 and 29, respectively,and the aligned step plates 27 and between fire bricks 28 are a seriesof nozzle pipes 34, which are of a sufficient length to reach and openinto the central floor area 31 of the hearth 13 where burning isintended to take place. The nozzle pipes 34 each have a series of ports35 in communication with their related plenums 25 and 30, respectively,and one end of each of these nozzle pipes also have a removable plug 36,accessible through the frame 19, to permit them to be reamed forcleaning purposes upon removal of the plugs. These nozzle pipes 34 mayalso be slightly pitched toward the central burning area 31, preferablyabout 3°-6°, to inhibit lodging of ash particles therein and forself-cleaning by the gently flowing air passing through the nozzlepipes.

The upper end of the frame 19 carries shelf-like angle plates 37, whichextend over the upper wall of the small channels 29 to prevent escape ofsmall burning particles from the central burning area 31. These plates37 also each carry along their longitudinal edges a bracket 38 to whichis connected a pair of spring-like sealing arms 39, and the outsidewalls of the small channels 29 each carry along their edges alongitudinally extending bracket 40, to which is connected an upstandingsealing strip 41 spring fit between the spring sealing arms 39 (see FIG.3a). At the charging end of the hearth 13, the exterior of thesuperstructure 21 (see FIG. 4) has another seal bracket 38a carryingdouble finger spring strips 41a rubbing against an extension 19a of theframe 19 for sealing the end of the moving hearth in a manner similar tothe hearth side arms 39--strip 41 described above.

Angular plates 37 also have depending therefrom a plurality of togglemembers 20, which may comprise toggle brackets 42 mounted to the frame19, through each of which extends a first pivot axle pin 43, and togglelinks 44 are pivotally connected to each of said axle pins 43. The otherend of each of said toggle links 44 have pivotally secured thereto asecond pivotal axle pin 45, and the side plates 23 and large channels 24have connected, as by welding, to their outside walls a toggle lug 46,which is pivotally secured to the second pivotal axle pin 45. Thesetoggle lugs 46 may be suitably reinforced by angle plates 47 secured tothe outside walls of the large tubular channels 24.

At the charging end of the hearth 13, the large channels 24 each extendbeyond the end of the hearth to form a U-shaped yoke 50. Likewise, thesuspension frame 19 is extended to provide an air bag frame whichconsists of a header beam 51 on one side of the yoke 50 and an impactbeam 52 on the other side of the yoke. The header beam 51 has spacedapart along its length a plurality of like air bags 53, each of which issecured inflatable to that beam by a bracket 54 facing one side of theyoke 50. Yoke 50 has secured thereon in alignment with the air bags 53push plates 55. The impact beam 52 has arranged along its length,preferably in alignment with each of the header beam air bags 53,carried on the impact beam by brackets 56, another set of air bags, theend air bags 57 of which set are enclosed in a cushioning frame 58 andthe central air bags 59 of which set are exposed. The side of the yoke50 facing the impact beam 52 has impact plates 60 aligned with theimpact beam air bags 57 and 59.

Spacing and aligning of the header and impact beams 51 and 52,respectively, relative to the yoke 50, may be set and maintained by rods61 secured one end to each of said beams. Stops 62, preferably mountedon the respective beams 51 and 52, may be provided adjacent each of saidair bags 53 and 57 and 59, respectively. Arms 63 may be secured to theheader beam 51 for carrying thereon an accummulator tank 64, which maycontain compressed air.

Preferably, upper walls 65 of the burning area 31 consist of a body ofrefractory and are tapered from the overhanging shelf-like plates 37toward the edges of the underlying bricks 28, and, like the refractorybodies 32 and 33 are suitably secured to the superstructure 21 by meansof refractory anchors 66.

GANGED HEARTHS

In very large incinerators or where a longer incineration time isdesired, similar hearths 13 may be ganged in line along theirlongitudinal axes by use of the structure shown in FIG. 8, providing acentral burning area 71 on a first hearth, which feeds burning materialto a second hearth like the hearth 13, having a central burning area 31,shown in FIG. 2.

Such ganging of hearths is achieved by extending rods 72 and a plate 73from the side edge and its underlying structure of a typical pulsatablehearth 13 (shown in FIG. 2) and covering the rods and plate with a bodyof refractory material 75. These rods 72, plate 73 and body 75 arearranged over the next adjacent hearth, e.g. the aforementionedstructure is elevated and extends over the tapered wall 32 (see FIG. 2)on the next adjacent hearth. Piles of particles burning in the centralburning area 71 are shuffled thereacross onto the body of refractorymaterial 75, as shown in FIG. 8, where they fall onto the next adjacenthearth, for example, onto the central burning area 31 of the hearthshown in FIG. 2.

Preferably, each of the pulsating hearths have their own suspension andmeans for delivering pulsating strokes to the hearths, as describedherein.

IMPACT CUSHIONS

As shown in FIG. 11, an impact bumper 80, preferably a sheet of rubberof about 40 durometer having a typical thickness of about 3 inches, maybe substituted for the end air bags 57 and their cushioning frames 58(shown in FIGS. 4 and 5), but secured to the brackets 56 shown. A bumperplate 81, aligned with the impact bumper 80, may be mounted on the plate60 secured to the yoke 50. In this arrangement, impact plate 81 on yoke50 is thrust and bounced against bumper 80 on the impact beam 52,compressing the impact bumper to a typical thickness of about 1 inchduring the thrust of each initial pulsation stroke.

In all cases, even with this modified impact bumper arrangement, thecentral air bags 59 are preferably present and inflated for returningthe yoke 50 from its stroked position to its initial stroking positionshown in FIGS. 4 and 5.

STROKING SYSTEM

Stroking of the hearth(s) 13 by movement of the yoke 50 from its initialposition, i.e. against the header beam 51, thrust against the impactbeam 52, and returning the stroked yoke to its initial position, may beaccomplished by use of the stroking system shown in FIG. 10.

In this system, compressed air is delivered from a compressor (notshown) from the "IN" side of the line through an inlet valve intoconduit 101, which may have therein a filter, and is regulated by aregulator 111. This conduit 101 may also have a valve and pressure guageand a pressure switch therein. The conduit 101 is in flow communicationwith a branch conduit 102, which may be connected through a flexiblehose 112, where the conduit 102 divides into two legs, one leg of whichhaving another regulator 111 and a pressure guage and value, and theother leg of which may also have a valve, both legs being connected tothe accummulator of air receiver tank 64, which may have a pressureguage therein and a blow-down valve at the extreme end thereof.

Parallel conduits 103 lead from the tank 64 to three way solenoid valves105. The solenoid valves 105 also have exhaust lines 104 extendingtherefrom. Air lines 106 connect each of the solenoid valves 105 to eachof the air bags 53. Thus, when the solenoid valves 105 are open from thetank 64 to the air bags 53, air will rush into and very rapidly inflatethe air bags 53, causing them to expand immediately and kick the yoke50. Preferably, these solenoid valves 105 are adjustable within a rangeof about 5-150 lbs. and are adapted to open at about 80 psi.

Compressed air is also delivered through conduit 101 to another branchconduit 107, which has another regulator 111 therein, and which connectsto bumper and return air bag conduit 108, through a flexible hose 112and a check valve. This conduit 108 connects with parallel conduits 109leading to central air bags 59 and also has a relief line, havingtherein a pressure guage, and relief and control valves, terminating inmufflers 113 exhausting to atmosphere.

Also connected to the conduit 101 through a regulator 111, flexible hoseand check valve is the impact cushion conduit 110, leading to the endimpact cushioning air bags 57, and this line also may have therein apressure guage and relief valve. Preferably, pressure is steadilymaintained in these impact cushioning air bags 57, so that only as theylose pressure is air injected into them.

Air entering the bags 59 is not admitted with a surging action, as isthe case with air bags 53 where the air is rapidly injected into thesebags, and the filling of bags 59 is only sufficient to move the yoke 50from its thrust position against the impact beam 52 back to its initialposition against the header beam 51.

The exhaust lines 104 lead from the solenoid valves 105 to a collectorconduit 114 which terminates in a relief valve exhausting the conduit114 to atmosphere through a muffler 113. When the yoke 50 is stroked byair bags 53, the movement of the yoke may activate a limit switch 115,which closes the solenoid valves 105 and opens the bags 53 to bleedingto atmosphere through exhaust line 104 and conduit 114.

When the yoke 50 has been thrown toward the impact beam 52 and bouncedagainst the cushion air bags 57, the central bags 59 are filled throughline 109, thus returning the yoke 50 to its initial position against theair bags 53 on header beam 51.

The strength of the throw and its cushioning may be controlled by thepressure and sizing of conduits and components of the compressed airdelivery system. The interval between strokes can be controlled by timermechanism opening and closing the solenoid valves 105.

MODIFIED SUSPENSION MEMBERS

The toggle members 20, shown in FIGS. 6 and 7, are intended to providefree suspension of the hearth superstructure 21 from its suspensionframe 19 and uninhibited movement in a short limited arc, usually notmore than 4-8 inches, with sufficient momentum to impell the load ofrandom size burning particles randomly arranged in piles on the hearthand stoke the pile, thus moving the particles forward across the hearthand rearranging the piles. This free suspension and uninhibited swingingin the fashion described requires free movement of the toggle members insuch a way that the floor has relatively frictionless movement in adefined arc without canting the hearth to jam its swing. The togglelinks 44 pivotally arranged, preferably aided by swivel bearing joints43a, as shown in FIG. 6, is one means to provide such movement.

Another means is shown in FIGS. 12 and 13, where modified toggle members120 comprise cable links 121 suspended between pairs of pivotablebearing pulleys 123, one of the pair mounted on the toggle bracket 42and the other of the pair carried by the toggle lug 46.

ACCELERATION CURVE

By means of the structure and system described above, the desiredacceleration of the yoke 50 and its connected hearth 13 may be achieved.A typical acceleration curve, measured over time and distance, is shownin FIG. 9.

When the air bags 53 are inflated by opening of the solenoid valves 105,at point A on the FIG. 9 graph, the yoke is moved to point B of maximumpositive acceleration on its forward stroke. When the yoke 50 first hitsthe impact beam 52 at point B, negative acceleration begins, at whichtime the yoke has reached its maximum stroke, but the particles continueto be propelled forwardly, and the yoke 50 bounced against the impactbeam 52 at point D, yielding to the return of the yoke 50 pushed off bythe return air bags 59 until the yoke has come to rest against theheader beam 51 and its air bags 53 then deflated at point E.

This stroke measurement has been recorded on chart paper marked incentimeters, and with reference to the curve one centimeter of the chartrepresents about 0.2 second real time for the entire accelerationstroke, and the rate of acceleration, was 0.053 g per centimeter ofchart paper.

The rapid and traumatic acceleration and the aftershock following thebuild-up of momentum is demonstrated by the FIG. 9 acceleration curve,and such acceleration force is required to sufficiently overcome inertiafor movement of the particles and rearranging them in order to achieveboth adequate combustion and travel.

While a preferred embodiment and alternate and modified structure forthe pulsating hearth has been shown and described, many changes indetails and arrangement of the pulsating hearth may be made withoutdeparting from the scope or spirit of the invention. Accordingly, it isnot desired that the invention should be limited to the exactconstruction and system shown and described.

I claim:
 1. In a hearth for an incinerator, the improvement comprising afixed suspension frame and a superstructure suspended from said framefor limited arcuate movement of said superstructure relative to saidframe, said superstructure including a central area thereon adapted toreceive a pile of burning particles, and means for stroking and stoppingmovement of said superstructure relative to said frame to compelmovement of said particles when arranged on said burning area responsiveto each stroking and stopping of said superstructure, saidsuperstructure having a yoke extending from one side thereof and saidframe having a beam on each of opposed sides of said yoke definingpredetermined positions for stroking and stopping movement of saidsuperstructure relative to said frame.
 2. In a hearth for anincinerator, the improvement comprising a fixed suspension frame and asuperstructure suspended for limited arcuate movement of saidsuperstructure relative to said frame, said superstructure including acentral area thereon adapted to receive a pile of burning particles, andmeans for stroking and stopping movement of said superstructure relativeto said frame to compel movement of said particles when arranged on saidburning area responsive to each stroking and stopping of saidsuperstructure, said stroking and stopping means comprises a fluidsystem including inflatable air bags and means for rapidly inflatingsaid air bags upon each stroke of said stroking and stopping means. 3.In the hearth recited in claim 2, wherein said superstructure has a yokeextending from one side thereof and said frame has a beam on each ofopposed sides of said yoke defining predetermined positions for strokingand stopping movement of said superstructure relative to said frame andwherein said stroking and stopping means comprises said air bags on oneof said beams and impact cushion means on the other of said beams.
 4. Inthe hearth recited in claim 5, wherein one of said beams has fluidoperated means for moving said yoke away from said impact cushion means.5. In the hearth recited in claim 4, wherein said fluid system hascontrol means selectively operable to inflate said air bags and toactuate said fluid means for moving said yoke away from said impactcushion means.
 6. In the hearth recited in claim 5, wherein said controlmeans includes means for repeating operation of said stroking andstopping means.
 7. In the hearth recited in claim 2, wherein said fluidsystem comprises conduit for conveying compressed air, a compressed airreceiving tank connected to said conduit, said air bags being in flowcommunication with said tank, solenoid valve means for controllingdelivery of compressed air from said tank to said air bags, flow controlvalves and regulator means in said conduit, and control means foropening and closing said solenoid valve means and said flow controlvalves and regulator means.
 8. In the hearth recited in claim 1, whereineach of said beams has stops extending in the direction of said yoke. 9.In the hearth recited in claim 8, wherein said beams are connectedspaced apart in alignment with said yoke.
 10. In a hearth for anincinerator, the improvement comprising a fixed suspension frame and asuperstructure suspended for limited arcuate movement of saidsuperstructure relative to said frame, said superstructure including acentral area thereon adapted to receive a pile of burning particles, andmeans for stroking and stopping movement of said superstructure relativeto said frame to compel movement of said particles when arranged on saidburning area responsive to each stroking and stopping of saidsuperstructure, said superstructure including (1) plenum means fordelivering gently flowing air to said burning area, (2) tubular channelsdefining said plenum means, and (3) nozzle pipes extending in air flowcommunication with said plenum means through said superstructure to saidburning area, one end of each of said pipes having a plug accessiblethrough said frame.
 11. In a hearth for an incinerator, the improvementcomprising a fixed suspension frame and a superstructure suspended forlimited arcuate movement of said superstructure relative to said frame,said superstructure including a floor which has a central area thereonadapted to receive a pile of burning particles and side and platemembers enclosing a chamber for containing free flowing air and meansfor stroking and stopping movement of said superstructure relative tosaid frame to compel movement of said particles when arranged on saidburning area responsive to each stroking and stopping of saidsuperstructure.
 12. In the hearth recited in claim 11, wherein said sidemembers have tubular channels.
 13. In the hearth recited in claim 11,wherein said plate member comprises a step plate overlaid with brick andrefractory material defining said central burning area.
 14. In a hearthfor an incinerator, the improvement comprising a fixed suspension frameand a superstructure suspended from toggle members from said frame forlimited arcuate movement of said superstructure relative to said frame,each of said toggle members being coupled to first points on said frameand second points on said superstructure with the first point for aparticular toggle member being located above the second point for saidparticular toggle member, said superstructure including a central areathereon adapted to receive a pile of burning particles, and means forstroking and stopping movement of said superstructure relative to saidframe to compel movement of said particles when arranged on said burningarea responsive to each stroking and stopping of said superstructure.15. In the hearth recited in claim 14, wherein said toggle memberscomprise links pivotally connected to said superstructure.
 16. In thehearth recited in claim 14, wherein said toggle members comprise spacedapart pulleys, one of which pulleys is connected to said superstructure,and cable links connecting said pulleys.
 17. In the hearth recited inclaim 14, wherein said frame and said superstructure each carrycooperating seal members.
 18. In a hearth for an incinerator, theimprovement comprising a fixed suspension frame and a superstructuresuspended for limited arcuate movement of said superstructure relativeto said frame, said frame having a shelf-like extension extending overthe top edges of said superstructure, said superstructure including acentral area thereon adapted to receive a pile of burning particles, andmeans for stroking and stopping movement of said superstructure relativeto said frame to compel movement of said particles when arranged on saidburning area responsive to each stroking and stopping of saidsuperstructure.
 19. In a hearth for an incinerator, the improvementcomprising a fixed suspension frame and two superstructures alignedalong the same longitudinal axis with one of said superstructurespositioned elevated above the other of said superstructures with saidsuperstructure suspended from said frame for limited arcuate movement ofsaid superstructure relative to said frame, each of said superstructuresincluding a central area thereon adapted to receive a pile of burningparticles, and means for stroking and stopping movement of saidsuperstructure relative to said frame to compel movement of saidparticles when arranged on said burning areas responsive to eachstroking and stopping of said superstructures.
 20. In the hearth recitedin claim 19, wherein said elevated superstructure has extending from oneedge thereof a refractory covered extension.
 21. In the hearth recitedin claim 20 wherein the other of said superstructures has an end wallwhich is tapered toward its burning area, and said extension of saidelevated superstructure overlies said tapered wall.
 22. A method forburning random refuse in an incinerator comprising: placing through aninlet opening in said incinerator random sized burning particlesarranged in piles on the burning area of an incinerator hearth, strokingsaid hearth in an arcuate movement in one direction primarily from saidinlet opening to an outlet opening in said incinerator removed from saidinlet opening to lift the particles, sufficiently abruptly stoppingmovement of said hearth to, after said hearth has stopped moving in saidone direction, shuffle the particles across said burning area in saidone direction and stoke the particle piles, and returning the hearth ina direction opposed to said one direction to an initial strokingposition.
 23. In the method recited in claim 22, with the additionalstep of delivering gently flowing air to said burning area.
 24. In themethod of claim 23, further including controlling the lengths of saidtime intervals.
 25. In the method of claim 24 wherein the strengths ofthe stroking said hearth is controlled.
 26. In the method recited inclaim 25, wherein the rate of abruptly stopping the movement of saidhearth is controlled.
 27. In the hearth recited in claim 1 wherein saidframe includes positioning means for changing said predeterminedpositions of said beams relative to each other.
 28. In the hearthrecited in claim 6 further including timer means controlling thefrequency at which the operation of said stroking and stopping means isrepeated.
 29. In the hearth recited in claim 28, including means forcontrolling the strengths of the stroking movement of saidsuperstructure.
 30. In the hearth recited in claim 29 further includingmeans for controlling the stopping of the movement of saidsuperstructure relative to said frame.
 31. In a hearth for anincinerator having an inlet opening and an outlet opening removed fromsaid inlet opening, the improvement comprising a fixed suspension frameand a superstructure suspended for limited movement of saidsuperstructure relative to said frame, said superstructure including acentral area thereon to receive a pile of burning particles, impellingmeans coupled to said frame or superstructure for providing saidsuperstructure with first and second types of motion relative to saidframe with said first type of motion being faster than said second typeof motion, said first and second types of motion being in first andsecond directions, respectively, opposite to each other with said firstdirection being from said inlet opening to said outlet opening andhaving first and second accelerations, respectively, substantiallydifferent from each other to compel movement of said particles whenarranged on said burning area responsive to said first type of motion ofsaid superstructure.
 32. The improvement of claim 31 wherein said firstacceleration produces said type of motion in said first direction at ahigher speed than said second type of motion in said second direction.33. The improvement of claim 32 wherein said impelling means alsoprovides said superstructure with an upward component of motion.
 34. Theimprovement of claim 32 wherein said compelling means comprises a fluidsystem including inflatable air bags and means for rapidly inflatingsaid air bags upon each stroke of said impelling means.
 35. Theimprovement of claim 34 wherein said superstructure includes a yokeextending from one side thereof and said frame has a beam on each ofopposed sides of said yoke defining predetermined positions for thetermination of said first and second types of motion and wherein saidimpelling means comprises said air bags on one of said beams and impactcushion means on the other of said beams.
 36. The improvement of claim35 further including fluid operated means, on one of said beams, formoving said yoke away from said impact cushion means.
 37. Theimprovement of claim 36 wherein said fluid system has control meansselectively operable to inflate said air bags and to actuate said fluidmeans for moving said yoke away from said impact cushion means.
 38. Theimprovement of claim 37 wherein said control means includes means forrepeating operation of said impelling means at predetermined timeintervals.
 39. The improvement of claim 32 wherein said frame carries afirst cooperating seal member and said superstructure carries a secondcooperating seal member in close proximity to said first cooperatingseal member, said first and second seal members having freedom oflongitudinal motion relative to each other while substantiallypreventing the passage of gases between them.
 40. The improvement ofclaim 32 wherein said frame has a shelf-like extension extending overthe top edges of said superstructure.
 41. The improvement of claim 32wherein said superstructure is a first superstructure and furtherincluding a second superstructure with said first and secondsuperstructures aligned along the same longitudinal axis and one of saidfirst and second superstructures is positioned elevated above the otherof said first and second superstructures.
 42. The improvement of claim41 wherein said one superstructure has extending from one edge thereof arefractory covered extension.
 43. The improvement of claim 42 whereinsaid other of said superstructures has an end wall which is taperedtowards its burning area, and said extension of said one superstructureoverlies said tapered wall.
 44. In the hearth recited in claim 32,wherein said superstructure has plenum means for delivering gentlyflowing air to said burning area.
 45. In the hearth recited in claim 44,wherein said superstructure has tubular channels defining said plenummeans.
 46. In the hearth recited in claim 44, wherein nozzle pipesextend in air flow communication with said plenum means through saidsuperstructure to said burning area.
 47. In a hearth having a housing,an inlet opening in said housing and an outlet opening in said housingremoved from said inlet opening, the improvement comprising a fixedsuspension frame and a superstructure suspended for limited movement ofsaid superstructure relative to said frame in a first direction fromsaid inlet opening to said outlet opening, said superstructure includinga central area thereon adapted to receive a pile of burning particles,and impelling means for stroking and stopping movement of saidsuperstructure relative to said frame primarily in said first directionwith a first speed and in a second direction opposite to said firstdirection with a second speed slower than said first speed, to compelmovement of said particles when arranged on said burning area responsiveto each stroking and stopping of said superstructure.
 48. Theimprovement of claim 47 wherein said impelling means also provides saidsuperstructure, when moving in said first direction, with an upwardcomponent of motion.
 49. In a hearth for an incinerator, the improvementcomprising a fixed suspension frame and a superstructure suspended forlimited movement of said superstructure relative to said frame betweenfirst and second positions, said superstructure including a central areathereon adapted to receive a pile of burning particles and impellingmeans for moving said superstructure relative to said frame from saidfirst position to said second position and impact means, coupled to andhaving a substantially fixed location relative to said frame, for makingcontact with and stopping said superstructure at said second positionand inducing a shuddering of said superstructure while remaining nearsaid second position to compel movement of said particles when arrangedon said burning area responsive to the movement of said superstructurefrom said first to said second position.
 50. In a method for burningrandom refuse in an incinerator having an inlet opening and an outletopening removed from said inlet opening, the steps comprising: placingrandom sized particles arranged in piles on the burning area of anincinerator hearth, moving said hearth in a first direction from saidinlet opening to said outlet opening with a first speed to shuffle theparticles across said burning area in said first direction and stoke theparticle piles, and moving said hearth in a second direction opposed tosaid first direction with a second speed substantially less than saidfirst speed.
 51. In a method for burning random refuse in an incineratorhaving a housing, an inlet opening in said housing and an outlet openingin said housing removed from said inlet opening, the steps comprising:placing random sized particles arranged in piles on the burning area ofan incinerator hearth in said housing, moving said hearth in a firstdirection primarily from said inlet opening to said outlet opening witha first acceleration, and returning the hearth in a second directionopposed to said first direction with a second acceleration less thansaid first acceleration.
 52. The method of claim 51 further includinglifting said hearth while moving it in said first direction.
 53. Themethod of claim 52 wherein said steps of moving in said first directionand lifting are accomplished by moving said hearth with an arcuatemotion having a first component parallel to said first direction and asmaller second component in the upward vertical direction.
 54. In amethod for burning random refuse in an incinerator, the stepscomprising: placing random sized particles arranged in piles on theburning area of an incinerator hearth, moving said hearth in onedirection from a first position to a second position, impacting saidhearth against an object remaining substantially fixed relative to saidsecond position inducing a shuddering of said hearth while remaining atsaid second position, and returning the hearth in a direction opposed tosaid one direction to said first position.
 55. A method for burningrandom refuse in an incinerator comprising: placing random sized burningparticles arranged in piles on the burning area of an incineratorhearth, stroking said hearth in an arcuate movement in one direction tolift the particles, sufficiently abruptly stopping movement of saidhearth to, after said hearth has stopped moving in said one direction,shuffle the particles across said burning area in said one direction andstoke the particle piles, and returning said hearth in a directionopposed to said one direction to an initial stroking position, stoppingthe movement of said hearth for a predetermined period of time,repeating the foregoing steps at timed intervals.
 56. In the methodrecited in claim 55, wherein a compressed air system is provided forgenerating said stroking and returning action.
 57. In the method recitedin claim 56, with the additional step of controlling delivery of airthrough said compressed air system.